This will avoid a possible fault in ecryptfs_sync_page().
In the function, eCryptfs calls sync_page() method of a lower filesystem
without checking its existence. However, there are many filesystems that
don't have this method including network filesystems such as NFS, AFS, and
so forth. They may fail when an eCryptfs page is waiting for lock.
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Acked-by: Michael Halcrow <mhalcrow@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
When ecryptfs_lookup() is called against special files, eCryptfs generates
the following errors because it tries to treat them like regular eCryptfs
files.
Error opening lower file for lower_dentry [0xffff810233a6f150], lower_mnt [0xffff810235bb4c80], and flags [0x8000]
Error opening lower_file to read header region
Error attempting to read the [user.ecryptfs] xattr from the lower file; return value = [-95]
Valid metadata not found in header region or xattr region; treating file as unencrypted
For instance, the problem can be reproduced by the steps below.
# mkdir /root/crypt /mnt/crypt
# mount -t ecryptfs /root/crypt /mnt/crypt
# mknod /mnt/crypt/c0 c 0 0
# umount /mnt/crypt
# mount -t ecryptfs /root/crypt /mnt/crypt
# ls -l /mnt/crypt
This patch fixes it by adding a check similar to directories and
symlinks.
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Acked-by: Michael Halcrow <mhalcrow@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
ecryptfs_init() exits without doing any cleanup jobs if
ecryptfs_init_messaging() fails. In that case, eCryptfs leaves
sysfs entries, leaks memory, and causes an invalid page fault.
This patch fixes the problem.
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Acked-by: Michael Halcrow <mhalcrow@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
When ecryptfs_lookup() is called against special files, eCryptfs generates
the following errors because it tries to treat them like regular eCryptfs
files.
Error opening lower file for lower_dentry [0xffff810233a6f150], lower_mnt [0xffff810235bb4c80], and flags
[0x8000]
Error opening lower_file to read header region
Error attempting to read the [user.ecryptfs] xattr from the lower file; return value = [-95]
Valid metadata not found in header region or xattr region; treating file as unencrypted
For instance, the problem can be reproduced by the steps below.
# mkdir /root/crypt /mnt/crypt
# mount -t ecryptfs /root/crypt /mnt/crypt
# mknod /mnt/crypt/c0 c 0 0
# umount /mnt/crypt
# mount -t ecryptfs /root/crypt /mnt/crypt
# ls -l /mnt/crypt
This patch fixes it by adding a check similar to directories and
symlinks.
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Acked-by: Michael Halcrow <mhalcrow@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Fix page index to offset conversion overflows in buffer layer, ecryptfs,
and ocfs2.
It would be nice to convert the whole tree to page_offset, but for now
just fix the bugs.
Signed-off-by: Nick Piggin <npiggin@suse.de>
Cc: Michael Halcrow <mhalcrow@us.ibm.com>
Cc: Mark Fasheh <mark.fasheh@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Slab destructors were no longer supported after Christoph's
c59def9f22 change. They've been
BUGs for both slab and slub, and slob never supported them
either.
This rips out support for the dtor pointer from kmem_cache_create()
completely and fixes up every single callsite in the kernel (there were
about 224, not including the slab allocator definitions themselves,
or the documentation references).
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
There is another bug recently introduced into the ecryptfs_setattr()
function in 2.6.22. eCryptfs will attempt to treat special files like
regular eCryptfs files on chmod, chown, and so forth. This leads to a NULL
pointer dereference. This patch validates that the file is a regular file
before proceeding with operations related to the inode's crypt_stat.
Thanks to Ryusuke Konishi for finding this bug and suggesting the fix.
Signed-off-by: Michael Halcrow <mhalcrow@us.ibm.com>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Following was uncovered by compiling the kernel with '-W' flag:
CC [M] fs/ecryptfs/inode.o
fs/ecryptfs/inode.c: In function ‘ecryptfs_lookup’:
fs/ecryptfs/inode.c:304: warning: comparison of unsigned expression < 0 is always false
fs/ecryptfs/inode.c: In function ‘ecryptfs_symlink’:
fs/ecryptfs/inode.c:486: warning: comparison of unsigned expression < 0 is always false
Function ecryptfs_encode_filename() can return -ENOMEM, so change the
variables to plain int, as in the first case the only real use actually
expects int, and in latter case there is no use beoynd the error check.
Signed-off-by: Mika Kukkonen <mikukkon@iki.fi>
Cc: Michael Halcrow <mhalcrow@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
sysfs is now completely out of driver/module lifetime game. After
deletion, a sysfs node doesn't access anything outside sysfs proper,
so there's no reason to hold onto the attribute owners. Note that
often the wrong modules were accounted for as owners leading to
accessing removed modules.
This patch kills now unnecessary attribute->owner. Note that with
this change, userland holding a sysfs node does not prevent the
backing module from being unloaded.
For more info regarding lifetime rule cleanup, please read the
following message.
http://article.gmane.org/gmane.linux.kernel/510293
(tweaked by Greg to not delete the field just yet, to make it easier to
merge things properly.)
Signed-off-by: Tejun Heo <htejun@gmail.com>
Cc: Cornelia Huck <cornelia.huck@de.ibm.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
They can use generic_file_splice_read() instead. Since sys_sendfile() now
prefers that, there should be no change in behaviour.
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
When one llseek's past the end of the file and then writes, every page past
the previous end of the file should be cleared. Trevor found that the code,
as is, does not assure that the very last page is always cleared. This patch
takes care of that.
Signed-off-by: Michael Halcrow <mhalcrow@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Recent changes in eCryptfs have made it possible to get to ecryptfs_setattr()
with an uninitialized crypt_stat struct. This results in a wide and colorful
variety of unpleasantries. This patch properly initializes the crypt_stat
structure in ecryptfs_setattr() when it is necessary to do so.
Signed-off-by: Michael Halcrow <mhalcrow@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This patch fixes the processes involved in wiping regions of the data during
truncate and write events, fixing a kernel hang in 2.6.22-rc4 while assuring
that zero values are written out to the appropriate locations during events in
which the i_size will change.
The range passed to ecryptfs_truncate() from ecryptfs_prepare_write() includes
the page that is the object of ecryptfs_prepare_write(). This leads to a
kernel hang as read_cache_page() is executed on the same page in the
ecryptfs_truncate() execution path. This patch remedies this by limiting the
range passed to ecryptfs_truncate() so as to exclude the page that is the
object of ecryptfs_prepare_write(); it also adds code to
ecryptfs_prepare_write() to zero out the region of its own page when writing
past the i_size position. This patch also modifies ecryptfs_truncate() so
that when a file is truncated to a smaller size, eCryptfs will zero out the
contents of the new last page from the new size through to the end of the last
page.
Signed-off-by: Michael Halcrow <mhalcrow@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Delay writing 0's out in eCryptfs after a seek past the end of the file
until data is actually written.
http://www.opengroup.org/onlinepubs/009695399/functions/lseek.html
``The lseek() function shall not, by itself, extend the size of a
file.''
Without this fix, applications that lseek() past the end of the file without
writing will experience unexpected behavior.
Signed-off-by: Michael Halcrow <mhalcrow@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
First thing mm.h does is including sched.h solely for can_do_mlock() inline
function which has "current" dereference inside. By dealing with can_do_mlock()
mm.h can be detached from sched.h which is good. See below, why.
This patch
a) removes unconditional inclusion of sched.h from mm.h
b) makes can_do_mlock() normal function in mm/mlock.c
c) exports can_do_mlock() to not break compilation
d) adds sched.h inclusions back to files that were getting it indirectly.
e) adds less bloated headers to some files (asm/signal.h, jiffies.h) that were
getting them indirectly
Net result is:
a) mm.h users would get less code to open, read, preprocess, parse, ... if
they don't need sched.h
b) sched.h stops being dependency for significant number of files:
on x86_64 allmodconfig touching sched.h results in recompile of 4083 files,
after patch it's only 3744 (-8.3%).
Cross-compile tested on
all arm defconfigs, all mips defconfigs, all powerpc defconfigs,
alpha alpha-up
arm
i386 i386-up i386-defconfig i386-allnoconfig
ia64 ia64-up
m68k
mips
parisc parisc-up
powerpc powerpc-up
s390 s390-up
sparc sparc-up
sparc64 sparc64-up
um-x86_64
x86_64 x86_64-up x86_64-defconfig x86_64-allnoconfig
as well as my two usual configs.
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Use zero_user_page() instead of open-coding it.
Signed-off-by: Nate Diller <nate.diller@gmail.com>
Cc: Michael Halcrow <mhalcrow@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
SLAB_CTOR_CONSTRUCTOR is always specified. No point in checking it.
Signed-off-by: Christoph Lameter <clameter@sgi.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Jens Axboe <jens.axboe@oracle.com>
Cc: Steven French <sfrench@us.ibm.com>
Cc: Michael Halcrow <mhalcrow@us.ibm.com>
Cc: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
Cc: Miklos Szeredi <miklos@szeredi.hu>
Cc: Steven Whitehouse <swhiteho@redhat.com>
Cc: Roman Zippel <zippel@linux-m68k.org>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Dave Kleikamp <shaggy@austin.ibm.com>
Cc: Trond Myklebust <trond.myklebust@fys.uio.no>
Cc: "J. Bruce Fields" <bfields@fieldses.org>
Cc: Anton Altaparmakov <aia21@cantab.net>
Cc: Mark Fasheh <mark.fasheh@oracle.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Jan Kara <jack@ucw.cz>
Cc: David Chinner <dgc@sgi.com>
Cc: "David S. Miller" <davem@davemloft.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Remove includes of <linux/smp_lock.h> where it is not used/needed.
Suggested by Al Viro.
Builds cleanly on x86_64, i386, alpha, ia64, powerpc, sparc,
sparc64, and arm (all 59 defconfigs).
Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
I have never seen a use of SLAB_DEBUG_INITIAL. It is only supported by
SLAB.
I think its purpose was to have a callback after an object has been freed
to verify that the state is the constructor state again? The callback is
performed before each freeing of an object.
I would think that it is much easier to check the object state manually
before the free. That also places the check near the code object
manipulation of the object.
Also the SLAB_DEBUG_INITIAL callback is only performed if the kernel was
compiled with SLAB debugging on. If there would be code in a constructor
handling SLAB_DEBUG_INITIAL then it would have to be conditional on
SLAB_DEBUG otherwise it would just be dead code. But there is no such code
in the kernel. I think SLUB_DEBUG_INITIAL is too problematic to make real
use of, difficult to understand and there are easier ways to accomplish the
same effect (i.e. add debug code before kfree).
There is a related flag SLAB_CTOR_VERIFY that is frequently checked to be
clear in fs inode caches. Remove the pointless checks (they would even be
pointless without removeal of SLAB_DEBUG_INITIAL) from the fs constructors.
This is the last slab flag that SLUB did not support. Remove the check for
unimplemented flags from SLUB.
Signed-off-by: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Ensure pages are uptodate after returning from read_cache_page, which allows
us to cut out most of the filesystem-internal PageUptodate calls.
I didn't have a great look down the call chains, but this appears to fixes 7
possible use-before uptodate in hfs, 2 in hfsplus, 1 in jfs, a few in
ecryptfs, 1 in jffs2, and a possible cleared data overwritten with readpage in
block2mtd. All depending on whether the filler is async and/or can return
with a !uptodate page.
Signed-off-by: Nick Piggin <npiggin@suse.de>
Cc: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
We need to work on cleaning up the relationship between kobjects, ksets and
ktypes. The removal of 'struct subsystem' is the first step of this,
especially as it is not really needed at all.
Thanks to Kay for fixing the bugs in this patch.
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Switch cb_lock to mutex and allow netlink kernel users to override it
with a subsystem specific mutex for consistent locking in dump callbacks.
All netlink_dump_start users have been audited not to rely on any
side-effects of the previously used spinlock.
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
For the common "(struct nlmsghdr *)skb->data" sequence, so that we reduce the
number of direct accesses to skb->data and for consistency with all the other
cast skb member helpers.
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
ecryptfs_d_release() first dereferences a pointer (via
ecryptfs_dentry_to_lower()) and then afterwards checks to see if the
pointer it just dereferenced is NULL (via ecryptfs_dentry_to_private()).
This patch moves all of the work done on the dereferenced pointer inside a
block governed by the condition that the pointer is non-NULL.
Signed-off-by: Michael Halcrow <mhalcrow@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
ecryptfs uses a lock_parent() function, which I hope really locks the parents
and is not abused
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Michael Halcrow <mhalcrow@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
- In fact we don't have to fail if AOP_TRUNCATED_PAGE was returned from
prepare_write or commit_write. It is beter to retry attempt where it
is possible.
- Rearange ecryptfs_get_lower_page() error handling logic, make it more clean.
Signed-off-by: Dmitriy Monakhov <dmonakhov@openvz.org>
Acked-by: Michael Halcrow <mhalcrow@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
- Currently after path_lookup succeed we dot't have any guarantie what
it is DIR. This must be explicitly demanded.
- path_lookup can't return negative dentry, So inode check is useless.
Signed-off-by: Dmitriy Monakhov <dmonakhov@openvz.org>
Acked-by: Michael Halcrow <mhalcrow@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
- ecryptfs_write_inode_size_to_metadata() error code was ignored.
- i_op->setxattr() must be supported by lower fs because used below.
Signed-off-by: Monakhov Dmitriy <dmonakhov@openvz.org>
Acked-by: Michael Halcrow <mhalcrow@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Dmitriy Monakhov wrote:
> if path_lookup() return non zero code we don't have to worry about
> 'nd' parameter, but ecryptfs_read_super does path_release(&nd) after
> path_lookup has failed, and dentry counter becomes negative
Do not do a path_release after a path_lookup error.
Signed-off-by: Michael Halcrow <mhalcrow@us.ibm.com>
Cc: Dmitriy Monakhov <dmonakhov@openvz.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
O_LARGEFILE should be set here when opening the lower file.
Signed-off-by: Michael Halcrow <mhalcrow@us.ibm.com>
Cc: Dmitriy Monakhov <dmonakhov@openvz.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
eCryptfs lower file handling code has several issues:
- Retval from prepare_write()/commit_write() wasn't checked to equality
to AOP_TRUNCATED_PAGE.
- In some places page wasn't unmapped and unlocked after error.
Signed-off-by: Michael Halcrow <mhalcrow@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Add format specifier %d for uid in ecryptfs_printk
Signed-off-by: Thomas Hisch <t.hisch@gmail.com>
Cc: Michael Halcrow <mhalcrow@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
eCryptfs is gobbling a lot of stack in ecryptfs_generate_key_packet_set()
because it allocates a temporary memory-hungry ecryptfs_key_record struct.
This patch introduces a new kmem_cache for that struct and converts
ecryptfs_generate_key_packet_set() to use it.
Signed-off-by: Michael Halcrow <mhalcrow@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
After Al Viro (finally) succeeded in removing the sched.h #include in module.h
recently, it makes sense again to remove other superfluous sched.h includes.
There are quite a lot of files which include it but don't actually need
anything defined in there. Presumably these includes were once needed for
macros that used to live in sched.h, but moved to other header files in the
course of cleaning it up.
To ease the pain, this time I did not fiddle with any header files and only
removed #includes from .c-files, which tend to cause less trouble.
Compile tested against 2.6.20-rc2 and 2.6.20-rc2-mm2 (with offsets) on alpha,
arm, i386, ia64, mips, powerpc, and x86_64 with allnoconfig, defconfig,
allmodconfig, and allyesconfig as well as a few randconfigs on x86_64 and all
configs in arch/arm/configs on arm. I also checked that no new warnings were
introduced by the patch (actually, some warnings are removed that were emitted
by unnecessarily included header files).
Signed-off-by: Tim Schmielau <tim@physik3.uni-rostock.de>
Acked-by: Russell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This patch is inspired by Arjan's "Patch series to mark struct
file_operations and struct inode_operations const".
Compile tested with gcc & sparse.
Signed-off-by: Josef 'Jeff' Sipek <jsipek@cs.sunysb.edu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Many struct inode_operations in the kernel can be "const". Marking them const
moves these to the .rodata section, which avoids false sharing with potential
dirty data. In addition it'll catch accidental writes at compile time to
these shared resources.
Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Call flush_dcache_page() after modifying a pagecache by hand.
Signed-off-by: Michael Halcrow <mhalcrow@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Replace kmap() with kmap_atomic(). Reduce the amount of time that mappings
are held.
Signed-off-by: Michael Halcrow <mhalcrow@us.ibm.com>
Signed-off-by: Trevor Highland <tshighla@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
sys_write() takes a local copy of f_pos and writes that back
into the struct file. It does this so that two concurrent write()
callers don't make a mess of f_pos, and of the file contents.
ecryptfs should be calling vfs_write(). That way we also get the fsnotify
notifications, which ecryptfs presently appears to have subverted.
Convert direct calls to f_op->write() into calls to vfs_write().
Signed-off-by: Michael Halcrow <mhalcrow@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Provide an option to provide a view of the encrypted files such that the
metadata is always in the header of the files, regardless of whether the
metadata is actually in the header or in the extended attribute. This mode of
operation is useful for applications like incremental backup utilities that do
not preserve the extended attributes when directly accessing the lower files.
With this option enabled, the files under the eCryptfs mount point will be
read-only.
Signed-off-by: Michael Halcrow <mhalcrow@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Generalize the metadata reading and writing mechanisms, with two targets for
now: metadata in file header and metadata in the user.ecryptfs xattr of the
lower file.
[akpm@osdl.org: printk warning fix]
[bunk@stusta.de: make some needlessly global code static]
Signed-off-by: Michael Halcrow <mhalcrow@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This patch set introduces the ability to store cryptographic metadata into an
lower file extended attribute rather than the lower file header region.
This patch set implements two new mount options:
ecryptfs_xattr_metadata
- When set, newly created files will have their cryptographic
metadata stored in the extended attribute region of the file rather
than the header.
When storing the data in the file header, there is a minimum of 8KB
reserved for the header information for each file, making each file at
least 12KB in size. This can take up a lot of extra disk space if the user
creates a lot of small files. By storing the data in the extended
attribute, each file will only occupy at least of 4KB of space.
As the eCryptfs metadata set becomes larger with new features such as
multi-key associations, most popular filesystems will not be able to store
all of the information in the xattr region in some cases due to space
constraints. However, the majority of users will only ever associate one
key per file, so most users will be okay with storing their data in the
xattr region.
This option should be used with caution. I want to emphasize that the
xattr must be maintained under all circumstances, or the file will be
rendered permanently unrecoverable. The last thing I want is for a user to
forget to set an xattr flag in a backup utility, only to later discover
that their backups are worthless.
ecryptfs_encrypted_view
- When set, this option causes eCryptfs to present applications a
view of encrypted files as if the cryptographic metadata were
stored in the file header, whether the metadata is actually stored
in the header or in the extended attributes.
No matter what eCryptfs winds up doing in the lower filesystem, I want
to preserve a baseline format compatibility for the encrypted files. As of
right now, the metadata may be in the file header or in an xattr. There is
no reason why the metadata could not be put in a separate file in future
versions.
Without the compatibility mode, backup utilities would have to know to
back up the metadata file along with the files. The semantics of eCryptfs
have always been that the lower files are self-contained units of encrypted
data, and the only additional information required to decrypt any given
eCryptfs file is the key. That is what has always been emphasized about
eCryptfs lower files, and that is what users expect. Providing the
encrypted view option will provide a way to userspace applications wherein
they can always get to the same old familiar eCryptfs encrypted files,
regardless of what eCryptfs winds up doing with the metadata behind the
scenes.
This patch:
Add extended attribute support to version bit vector, flags to indicate when
xattr or encrypted view modes are enabled, and support for the new mount
options.
Signed-off-by: Michael Halcrow <mhalcrow@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Public key support code. This reads and writes packets in the header that
contain public key encrypted file keys. It calls the messaging code in the
previous patch to send and receive encryption and decryption request
packets from the userspace daemon.
[akpm@osdl.org: cleab fix]
Signed-off-by: Michael Halcrow <mhalcrow@us.ibm.com>
Cc: David Howells <dhowells@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This is the transport code for public key functionality in eCryptfs. It
manages encryption/decryption request queues with a transport mechanism.
Currently, netlink is the only implemented transport.
Each inode has a unique File Encryption Key (FEK). Under passphrase, a File
Encryption Key Encryption Key (FEKEK) is generated from a salt/passphrase
combo on mount. This FEKEK encrypts each FEK and writes it into the header of
each file using the packet format specified in RFC 2440. This is all
symmetric key encryption, so it can all be done via the kernel crypto API.
These new patches introduce public key encryption of the FEK. There is no
asymmetric key encryption support in the kernel crypto API, so eCryptfs pushes
the FEK encryption and decryption out to a userspace daemon. After
considering our requirements and determining the complexity of using various
transport mechanisms, we settled on netlink for this communication.
eCryptfs stores authentication tokens into the kernel keyring. These tokens
correlate with individual keys. For passphrase mode of operation, the
authentication token contains the symmetric FEKEK. For public key, the
authentication token contains a PKI type and an opaque data blob managed by
individual PKI modules in userspace.
Each user who opens a file under an eCryptfs partition mounted in public key
mode must be running a daemon. That daemon has the user's credentials and has
access to all of the keys to which the user should have access. The daemon,
when started, initializes the pluggable PKI modules available on the system
and registers itself with the eCryptfs kernel module. Userspace utilities
register public key authentication tokens into the user session keyring.
These authentication tokens correlate key signatures with PKI modules and PKI
blobs. The PKI blobs contain PKI-specific information necessary for the PKI
module to carry out asymmetric key encryption and decryption.
When the eCryptfs module parses the header of an existing file and finds a Tag
1 (Public Key) packet (see RFC 2440), it reads in the public key identifier
(signature). The asymmetrically encrypted FEK is in the Tag 1 packet;
eCryptfs puts together a decrypt request packet containing the signature and
the encrypted FEK, then it passes it to the daemon registered for the
current->euid via a netlink unicast to the PID of the daemon, which was
registered at the time the daemon was started by the user.
The daemon actually just makes calls to libecryptfs, which implements request
packet parsing and manages PKI modules. libecryptfs grabs the public key
authentication token for the given signature from the user session keyring.
This auth tok tells libecryptfs which PKI module should receive the request.
libecryptfs then makes a decrypt() call to the PKI module, and it passes along
the PKI block from the auth tok. The PKI uses the blob to figure out how it
should decrypt the data passed to it; it performs the decryption and passes
the decrypted data back to libecryptfs. libecryptfs then puts together a
reply packet with the decrypted FEK and passes that back to the eCryptfs
module.
The eCryptfs module manages these request callouts to userspace code via
message context structs. The module maintains an array of message context
structs and places the elements of the array on two lists: a free and an
allocated list. When eCryptfs wants to make a request, it moves a msg ctx
from the free list to the allocated list, sets its state to pending, and fires
off the message to the user's registered daemon.
When eCryptfs receives a netlink message (via the callback), it correlates the
msg ctx struct in the alloc list with the data in the message itself. The
msg->index contains the offset of the array of msg ctx structs. It verifies
that the registered daemon PID is the same as the PID of the process that sent
the message. It also validates a sequence number between the received packet
and the msg ctx. Then, it copies the contents of the message (the reply
packet) into the msg ctx struct, sets the state in the msg ctx to done, and
wakes up the process that was sleeping while waiting for the reply.
The sleeping process was whatever was performing the sys_open(). This process
originally called ecryptfs_send_message(); it is now in
ecryptfs_wait_for_response(). When it wakes up and sees that the msg ctx
state was set to done, it returns a pointer to the message contents (the reply
packet) and returns. If all went well, this packet contains the decrypted
FEK, which is then copied into the crypt_stat struct, and life continues as
normal.
The case for creation of a new file is very similar, only instead of a decrypt
request, eCryptfs sends out an encrypt request.
> - We have a great clod of key mangement code in-kernel. Why is that
> not suitable (or growable) for public key management?
eCryptfs uses Howells' keyring to store persistent key data and PKI state
information. It defers public key cryptographic transformations to userspace
code. The userspace data manipulation request really is orthogonal to key
management in and of itself. What eCryptfs basically needs is a secure way to
communicate with a particular daemon for a particular task doing a syscall,
based on the UID. Nothing running under another UID should be able to access
that channel of communication.
> - Is it appropriate that new infrastructure for public key
> management be private to a particular fs?
The messaging.c file contains a lot of code that, perhaps, could be extracted
into a separate kernel service. In essence, this would be a sort of
request/reply mechanism that would involve a userspace daemon. I am not aware
of anything that does quite what eCryptfs does, so I was not aware of any
existing tools to do just what we wanted.
> What happens if one of these daemons exits without sending a quit
> message?
There is a stale uid<->pid association in the hash table for that user. When
the user registers a new daemon, eCryptfs cleans up the old association and
generates a new one. See ecryptfs_process_helo().
> - _why_ does it use netlink?
Netlink provides the transport mechanism that would minimize the complexity of
the implementation, given that we can have multiple daemons (one per user). I
explored the possibility of using relayfs, but that would involve having to
introduce control channels and a protocol for creating and tearing down
channels for the daemons. We do not have to worry about any of that with
netlink.
Signed-off-by: Michael Halcrow <mhalcrow@us.ibm.com>
Cc: David Howells <dhowells@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Replace appropriate pairs of "kmem_cache_alloc()" + "memset(0)" with the
corresponding "kmem_cache_zalloc()" call.
Signed-off-by: Robert P. J. Day <rpjday@mindspring.com>
Cc: "Luck, Tony" <tony.luck@intel.com>
Cc: Andi Kleen <ak@muc.de>
Cc: Roland McGrath <roland@redhat.com>
Cc: James Bottomley <James.Bottomley@steeleye.com>
Cc: Greg KH <greg@kroah.com>
Acked-by: Joel Becker <Joel.Becker@oracle.com>
Cc: Steven Whitehouse <swhiteho@redhat.com>
Cc: Jan Kara <jack@ucw.cz>
Cc: Michael Halcrow <mhalcrow@us.ibm.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Stephen Smalley <sds@tycho.nsa.gov>
Cc: James Morris <jmorris@namei.org>
Cc: Chris Wright <chrisw@sous-sol.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Change all the uses of f_{dentry,vfsmnt} to f_path.{dentry,mnt} in the
ecryptfs filesystem.
Signed-off-by: Josef "Jeff" Sipek <jsipek@cs.sunysb.edu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Ryusuke Konishi